Prop-withdrawing apparatus for use in mines



May '20, 1952 J.- B. MAVOR PROP-WITHDRAWING APPARATUS FOR USE IN MINES Filed Aug. 6, 1947 ATTORNEYS (INVENTOR my Patented May 20, 1952 PROP-WITHDRAWING APPARATUS FOR USE IN MINES John Bridie Mavor, Glasgow, Scotland, assignor Limited, Glasgow, Scotto Mavor & Coulson,

land

Application August 6, 1947, Serial No. 766,629 In Great Britain July 25, 1945 8 Claims. (Cl. 254-93) It is the practice to support the roof of mine workings by means of props, usually made either of timber or steel. As the roof settles, the props become subject to heavy load. To withdraw loaded props, prop-withdrawing apparatus is used, this being apparatus by means of which a strong lateral pull can .be applied to the foot or head of the prop, a high mechanical advantage being obtained from hand operation at a safe distance from the prop.

An object of this invention is to provide propwithdrawing apparatus comprising a transportable body with a motor-driven pump for the supply of fluid under pressure, a fluid pressure cylinder-and-ram unit operated by fluid from the pump, and an attachment device for connecting said unit to either the foot or the head of the prop to be withdrawn so as to exert the required pull on the prop.

Another object of this invention is to provide a vehicle with a fluid supply, a motor-driven pump drawing from said supply, a cylinder-and-ram unit, a valve for controlling the operation of said unit, and an attachment device on said unit by virtue of which the unit can be connected to either the foot or the head of a prop in order to exercise thereon a pull sufilcient for withdrawal thereof.

The apparatus may be anchored to an appropriately set roof-supporting prop as is customary with hand-operated apparatus, or the apparatus may have provision of its own for anchorage.

The invention will now be described by way of example with reference to the accompanying drawing, in Which- Fig. 1 is a side elevation of one construction of the apparatus including a wheeled vehicle, this view showing the apparatus positioned for use. Fig. 2 is an end elevation of the vehicle. Fig. 3 is a side elevation of the vehicle showing it at rest in an out-of-use position.

Fig. 4 is a view corresponding to Fig. 2, but showing a construction in which the vehicle is adapted to slide on a mine floor.

Referring to Fig. 1, the apparatus shown therein is positioned for use upon the floor A of the mine. The roof B of the mine is shown supported by a prop C about to be withdrawn by the apparatus.

In the construction of the apparatus according to Figs. 1 to 3, the body of the wheeled vehicle includes an under-carriage 6 provided at opposite sides with wheels 1 having an axle 8. The body also includes a horizontal hydraulic cylinder 9 which is arranged centrally at a low level, being at the level of the axle 8. The body also includes at a level above the hydraulic cylinder an oil tank Ill, a motor H (which may be either an electric motor or a compressed air motor), a pump l2 driven by the motor, and a control valve l3 having a hand-lever M for setting the valve in any of various available positions. The pump I2 is conventionally shown in Fig. 1, being of a type which is coupled directly to the motor I I without speed-reducing gearing. The pump is arranged in the oil tank ID, the suction side of the pump drawing oil directly from the tank. The discharge side of the pump is connected by a pipe [5 to the valve [3. Pipes l6 and I 1 connect the valve to opposite ends of the hydraulic cylinder 9. A return pipe [8 leads from the valve back to the oil tank. The cylinder 9 is a component of a hydraulic unit including also a ram 19 which protrudes from one end of the cylinder (the lefthand end in Fig. 1). The outer end of the ram is provided with a pivotal device 20 for attaching the ram to a cable 2|, one end 22 of which is connected to a clamp 23 secured to the foot of the prop C. The attachment device 20 may be of any appropriate construction, the example shown comprising two jaws 24 and 25 under the control of a manually turnable eccentric 26, the function of which is to force the upper jaw 24 to grip the cable 2| hard against the lower jaw 25. The attachment device is in the nature of a oneway clutch, the arrangement being such that the stronger the pull on the cable, the stronger the grip exercised by the jaws. At that end of the vehicle which is opposite to the rain (the right hand end, Fig. 1), a prop socket 2! is attached by a pair of side links 28 to the axle 8, this socket being adapted to receive the foot of an anchorage prop 29 which in the construction shown is telescopic, being made of steel and having pointed end fixtures 30 adapted to bite into the floor A and the roof B. The lower part of the vehicle is provided with a skid 3| upon which the vehicle rests when out of use (Fig. 3).

In order to use the apparatus, it is moved along the floor A of the mine into an appropriate position in relation to the prop C, which is usually set as shown at an inclination to the vertical. The anchorage prop 29 is fitted through the socket and is extended so that it is jammed between the floor and roof at an appropriate inclination. In this way the apparatus is accurately anchored i its chosen location.

The motor H is started and drives the pump l2. The hand-lever I 4 of the control valve is turned so that oil under pressure is admitted by and tank). The cable is attached to the prop G" to be withdrawn and is pulled towards=the:rig-ht through the attachment device 20 until it is taut. The eccentric 26 is manipulated so that the jaws 24, 25 securely grip the cable; Then the handlever I4 is positioned so that oil under" pressure is delivered from the pump by way of the pipe I! to the left-hand end of the cylinder; o'il from! the other end thereof being returned to the oil tank by way of the pipes 16 and I8. Accordingly the ram is forcibly withdrawn into the cylinder and exercises on the propC a pull which is strong enough to withdraw the prop.

In the-drawing (Fig. 1), theclamp 2-3 is-shown secured to there-t of the prop C. It-o'ften happens however that the securing" must be done at the head. --By virtue" ofthe pivotal relationship, through the axle" 8, between the hydraulic 11bit 9; l9 and the links 28, the hydraulic unit can be uptil ted into a position (namely; the rest position according to Fig. 3') in which said' unit is aligned with a pull directed tothe head of the prop, there being a sufiicie'n't length of cable 2 1 for the purpose; Thus it will'be'manifest that the. pun to the head of the prop can be exerted without" any tenden'cywhatsoever to lift the vehicle from th'e'fio'o'r (a tendency which would be of the greatest danger'ina coal-mine). Moreover, it' will be manifest that the pull (whether to'the foot or head 'of'th'epropl is takenthroug-h the pivotally" interconnected hydraulic unit- 9; f9 and links 28, the vehicleitself being relieved from' stresses due to the pull except as regards the desirable do'wi'iwar'd' pressure holding the vehicle to the floor;

In the construction according to Fig. 4',- the vehicle is thesame as described with' reference toFi gs. I to 3 with the exception that the vehicle is not wheeled but has a base in theform'of askid 32' which can slide uponthe mine fioor A. The-skid 342- is support'ed'by side struts 33 which hang-fromtheaxle 8 ofthe undercarriage 6. It will be manifest that, in this construction, the hydrauliccy-linder 9 (with the remainder of the body of-the-vehicle) is pivotal in relation to the floor-engaging supporting means 32 33, just as in the construction according to Figs; 1 to 3' the cylinder is pivotal in relation to the floor-engaging wheels 1. Thus, the unit 9;. l9" can be directed towards either the foot or head of-' the prop to bewithdrawn.

The constructions described are examples, and any of various modifications may be made. For instance, Fig. 1 shows the cable 2| as a rope; instead, l t-may bea chain; and the attachment device-may; be suchthat the cable is positively locked: tothe ram end.

I- claim:

1 Mine prop-withdrawing. apparatus comprising a transportable body with supporting means to engage the floor and a motor-driven pump for the supply of fluid under pressure, a fluid-pressure cylinder-and-ram unit operated by fluid from the pump, a pivotal connection' between said unit" and said supporting means by virtue ofwhichthe unit can be directed towards eitherthe foot or head of a prop to be withdrawn, and

an attachment device for connecting said unit to either the foot or the head of the prop to be Withdrawn so as to exert the required pull on the prop.

2. Mine prop-withdrawing apparatus compris i'n'ga vehicle with supporting'means tol'engage thefioor and Ellflllld supply; amotor driven pump drawing from said supply, a cylinder-and-ram unit operable by the fluid from the pump, a valve for controlling.- the operation of said unit, a pivotal': connection between said unit and said supporting means by virtue of which the unit can be directed towards-either the foot or head of aproptobe'wlthdi-awn, and an attachment device on said unitbYvirtue of which the unit can be connected-tar either the foot or the head of the prop in order to exercise thereon a pull sufficient for withdrawal thereof.

3. Mine prop-withdrawing apparatus comprising a transportable body with supporting means to 1 engagethe floor and a motor-driveirpump for the supply offluid und'er pressure, a fluid-pres.- sure cylinder-and -ram unit operated by fluid fromthepurhp; a pivotal connection between said unit and sa-id supporting means" by virtue of which the: unit can be directed towards either the foot or head-of a prop to be withdrawn}. an attachment device for connectingsaid unit to either the'foot or the head of the prop to be withdrawn so as to exert the requiredipulliorrithe propgandmeans connected to said unit for anchorin'g the 'transportable body-"to a mine floor so -that the pull is exertedthroughsaid unit and said: anchoring means;

4. Mine prop withdrawing:apparatuses claimed by claim-3 in'- which the anchoring means consist of a linkage pivotally connected to and extending' from said bodyand asock'e't on said linkage to receive an anchorage prop.

5. Mine prop withdrawi'ng' apparatus: comprising a vehicle with supporting means to engage thefloor and a fiuid supply g-a motor-drivenpump drawing from said supply; a cylinde'r-and-ram unit operable by the fluid fromthe' pump, a valve for controlling the' operation" of saidunit, a" pivotal connection between said unit and saidsupp'ortir-ig means by virtue: of which the unit can be directed towards either the foot or head of a prop to be withdrawn; an attachment device on saiduriit by: virtue of which the unit can be con nected to either the foot or the head of the prop in ordert'o exercise thereon a pul1 sufiicient' for withdrawal thereof, a linkage pivotally connected to and extending from said vehicle, and means on said linkage for attachment thereof to an anchorage prop.

6; Mine prop-withdrawing apparatus comprising a transportable body with supporting means to engage the floor and a motor-driven pump for the supply of fluid under pressure, a fluid-pressure cylinder-and-ram unit operated by fluid from' the pump, said unit comprising a movable component and a stationary component" which is pivotally mounted in relation to said supporting means so that said" unit can be directed towards either the foot or head of a prop to be withdrawn; and an" attachment device provided on said movable component for connecting it to a cable attachable to either the foot or the headof the prop" to be withdrawn so as to exert. thereon a pull sufficient for withdrawal thereof.

7. Mine prop-withdrawing apparatus comprising a vehicle with supporting means to" engage thefloor' and afiuid supply, a motor-drivenipump drawing from said supply; a cylinder-and ra'm 5 unit operable by the fluid from the pump, said unit comprising a movable component and a stationary component which is pivotally mounted in relation to supporting means so that said unit can be directed towards either the foot or head of a prop to be withdrawn, a valve for controlling the operation of said movable component, and

an attachment device provided on said movable component for connecting it to a cable attachable to either the foot or the head of the prop in order to exercise thereon a pull suificient for Withdrawal thereof.

8. Mine prop-withdrawing apparatus comprising a vehicle with supporting means to engage the floor and a fluid supply, a motor-driven pump drawing from said supply, a cylinder-and-ram unit operable by the fluid from the pump and consisting of a cylinder, which is a fixture on the vehicle but is pivotal in relation to said supporting means, and a ram which is movable in and extends from said cylinder, a valve for controlling the operation of said ram, and an attachment device on said ram by virtue of which the ram can be connected to either the foot or the head of a prop in order to exercise thereon a pull sufficient for withdrawal thereof.

JOHN BRIDIE- MAVORl REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,258,691 Long Mar. 12, 1918 1,746,920 Yencha et a1 Feb. 11, 1930 2,430,962 Stamler Nov. 18, 1947 

